Wilhelm von flotow and hermann leidig



METHOD OF DRAWING TUBES.

Patented Oct. 30, 1888..

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NITE'D STATES WILHELM VON FLOTOVV AND HERMANN LEIDIG, OF DANTZIO,PEUSSIA, GERMANY.

METHOD OF DRAWING TUBES.

SPECIFICATION forming part of Letters Patent No. 391,994, dated October30, 1888.

Application filed May 7,1887. Serial No.237,504.

(No model.) Patented in Germany March 15, 1887, No. 42,139; in FranceApiil 8, 1887, No. 182,751; in England April 9, 1887, No. 5,268; inBelgium April 12, 1887, No. 77,029; in Italy May 10,1887, No. 21,508,and in Anstriafiungary August 537, 1887, No. 18,195 and No. 19,235.

To aZZ whom it mag concern.-

Be it known that we, WILHELM VON FLorow and HERMANN LEIDIG, bothsubjects of the Emperor of Germany, residing at the city of Dantzic, inthe Kingdom of Prussia, Empire of Germany, have invented certain new anduseful Improvements in Drawing Seamless Metal Tubes, of which thefollowing is a specification.

For this invention we have obtained patents in the following countries:in Belgium, No. 77,029, dated April 12, 1887; in England, No. 5,268,dated April 9, 1887; in France, No. 182,751, dated April 8, 1887; inItaly, No. 21,508, dated May 10, 1887; in Austria-Hungary, No. 18,195and No. 19,235, dated August 27, 1887, and in Germany, No. 42,139, datedMarch 15, 1887.

The object of our invention is to draw in a cold state tubes thediameter of which decreases successively in offsets.

The invention consists in drawing a tube in a cold state successivelythrough openings of decreasing diameter.

In the accompanying drawings, Figure 1 is a vertical longitudinalsection of the blank for drawing a tube the diameter of which decreasessuccessively in offsets. Fig. 2 isa similar sectional view of the blanktube prepared for the drawing operation. Fig. 3 is a similar sectionalview of the tube after it has been drawn. Figs. 1 and 5 are similarsectional views of the tubes, showing the dies used and showingdifferent methods of drawing the tubes.

Similar letters of reference indicate corresponding parts.

One end of the blank tube A is reduced in diameter to form theholding-lug z for the drawing-tool. The tube A is then drawn in a coldstate successively through a series of dies, the diameter of the openingof each die being slightly smaller than that of the preceding die,

and so on, whereby a tube is obtained, as shown in Fig. 3, said tubehaving a series of annular offsets, a, and at each ofiset the diameterof the tube decreases slightly. The tube is not drawn entirely througheach die, but through the first die it is drawn to within a shortdistance of the larger end. Through the second die it is drawn to withintwice this length from the larger end, through the third die to threetimes the distance from thelarger end, and so on. The offsets on theinside and outside can then be turned or ground off.

As shown in Fig. 4, the dies B can be made tapered on the inside, so asto reduce the height of the offsets, or to make a tapered tube withoutoffsets, the inclination of the several dies being alike.

If desired, a rod, D, (shown in Fig. 5,) may be inserted in the tube Ain such a manner that the offset D at its free end rests against thefront contracted end of the blank. By means of the head 0 pressure isexerted on the opposite end of the said rod and thereby the blank isdrawn through the several. dies.

Having thus described our invention, we claim as new and desire tosecure by Letters Patent The method, substantially as herein shown anddescribed, of drawing tubes having succcssivclydecreasing diameters,consisting in successively drawing the different parts of the length ofthe tube through difi'eren't dies having openings of differentdiameters, substantially as set forth.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

WILHELM VON FLOTOW. I-IERMANN LEIDIG.

lVitnesscs:

LOUISE KURTZ, ERDMANN.

